Prevent hardcoding of if condition in bash - bash

Question

Following is my sample code which is setting environment settings to the session. I am getting env setting name as first argument of the function and storing it to supplied_env , I have a list of possible environments which contains possible or allowed environments allowed for this script. I have to keep this list hard coded which is acceptable. However in the end just before sourcing the environment file, I have to run if condition with hardcoded environment name(env1 or env2). Is there any way to only keep the environment names hardcoded only at the beginning and match them dynamically later ?
#!/bin/bash
supplied_env="${1}"
possible_env="env1 env2"
if [ $# -ne 1 ];then
echo "You must provide any one of these values ${possible_env}"
exit 1;
elif ! echo "${possible_env}"|grep "$supplied_env" ;then
echo "Incorrect value provided, You must provide any one of these values ${possible_env}"
exit 2;
else
target_env=${supplied_env}
fi
if [ ${supplied_env} == "env1" ];then #<------How to avoid using `env1` string here, rather get it from possible_env ?
source ~/.env1
elif [ ${supplied_env} == "env2" ];then
source ~/.env2
else
echo "Error..."
fi
In short, in future there would be move environments like env3 ,env4 etc. I just want to update the script at one place not at multiple places.

Answer 1

if [ ${supplied_env} == "env1" ];then #<------How to avoid using `env1` string here, rather get it from possible_env ?
source ~/.env1
elif [ ${supplied_env} == "env2" ];then
source ~/.env2
else
echo "Error..."
fi
You can substitute $supplied_env in the source statement. Since you've already done error checking you don't need any other logic, just a single source call.
source ~/."$supplied_env"

Answer 2

Store the allowed names as keys in an associative array.
declare -A possible_env=([env1]=~/.env1 [env2]=~/.env2)
Then you can check for the existence of a key in this array.
supplied_env="${1:?Must supply an environment name}"
declare -A possible_env=([env1]=~/.env1 [env2]=~/.env2)
if [[ ! -v possible_env[$suppliedEnv] ]]; then
echo "Incorrect value provided, You must provide any one of these values: ${!possible_env[*]}"
exit 2;
fi
source "${possible_env[$suppliedEnv]"